I had a bit of a blast to Abergavenny and back to Bristol, had a hoot, so I'm calling my bike sorted. There were none of the original issues, the only thing left being this irritating rev drop, which now happens very distinctly when the bike is NOT under any load, trickling down to a stop, between 2nd and first gear. I can make it do this repeatedly, so I can avoid it, but I suspect this is a deliberate 'feature' in the system, probably to do with saving the Planet. I'd like it removed, it is potentially dangerous, but all the other other problems I had seem to have gone. The bike is now a pleasure to ride, I don't feel like it is about to die on me all the time, it pulls cleanly, has not coughed or backfired once, and my fuel economy is creeping up again, no doubt because I am happier running the bike in lower revs, ie 4 thousand, where the torque is at its maximum. Before, it would pull fine at this point, but the moment the revs started to drop a bit, it would go all vague.... Not now. I can change gear cleanly, most of the time, because I can now control the revs to what I want, rather than wherever the problem, whatever it was, left them floating about.
I'll speak with Frasers, obviously it would be good to know what precisely was at fault, but bottom line, I'm a happy bunny now, I have the bike I knew was there all along. Just sorry it took so long to nail.
To anyone else with the same issues, Frasers swapped out the ENTIRE throttle assembly, with the same parts on their demonstrator. I'll find out if they have put my old parts back in their bike, or, put in a new set. I wouldn't want a demonstrator with a known duff carb set in it! I'll pass on any details I find out, if anything.
So:
!
Tim